• Before starting, preheat the broiler to high.
• Wash and dry all produce.
• Bring a large pot of salted water to a boil (use same for 4 servings).
• Meanwhile, core, then cut pepper into 1/2-inch pieces.
• Peel, then mince or grate garlic. 
• Roughly chop parsley.
• Roughly chop spinach.
• To the ricotta container, add 1/4 tsp (1/2 tsp) garlic salt and 1/8 tsp (1/4 tsp) chili flakes. (Like things spicy? Add more chili flakes!) Season with pepper, then stir to combine.
• Pat chicken dry with paper towels. Cut into 1/2-inch pieces. Season with salt and pepper. 

• To the boiling water, add rigatoni. Cook for 12-13 min, stirring occasionally, until tender but still firm to the bite.
• Reserve 1/4 cup (1/2 cup) pasta water.
• Strain rigatoni, then return to the pot, off heat.

• Meanwhile, heat a medium oven-proof pan (large oven-proof pan for 4 servings) over medium.
• When hot, add 1 tbsp (2 tbsp) oil, then chicken and peppers. Season with salt and pepper. 
• Cook for 6-8 min, stirring occasionally, until peppers are tender and chicken is cooked through.**

• To the pan with chicken and peppers, add garlic and remaining garlic salt, then season with pepper. Cook for 30 sec, stirring often, until fragrant. 
• Add crushed tomatoes, broth concentrate and 1/2 tsp (1 tsp) sugar. Bring to a simmer, then reduce heat to medium-low.
• Cook for 5-8 min, stirring occasionally, until sauce thickens slightly.

• To the pan with sauce, add rigatoni, spinach, reserved pasta water and half the mozzarella.
• Season with salt and pepper, then toss to combine. (NOTE: If you don't have an oven-proof pan, transfer to an 8x8-inch 
  [9x13-inch] baking dish.)
• Sprinkle with remaining mozzarella, then dollop seasoned ricotta over top.
• Broil in the middle of the oven for 3-5 min, until cheese is golden.

• Let rigatoni al forno cool for 5 min.
• Divide between plates.
• Sprinkle parsley over top.
• Sprinkle with remaining chili flakes, if you like.

If you've opted to add chicken breasts, pat chicken dry with paper towels. Cut into 1/2-inch pieces. Season with salt and pepper. 

When the pan is hot, add chicken along with 1 tbsp (2 tbsp) oil and peppers. Cook for 6-8 min, stirring occasionally, until peppers are tender and chicken is cooked through.** Follow the rest of the recipe as written.